Corncob burner



Jan. 19, 1954 w; POL 2,666,403

CORNCOB BURNER Filed July 13, 1951 2 Sheets-Sheet l INVENTOR WALTER C. Q-K BY MW A WORNEYS Jan. 19, 1954 w, c, POLK 2,666,403

CORNCOB BURNER Filed July 13, 1951 2 Sheets-Sheet 2 LO '1 Q5 8 Fig.2

INVENTOR WALTER C. PoLK Patented Jan. 19, 1954 2,666,403 CORNCOB BURNERWalter 0. Polk, Fort Branch, Ind. Application July 13, 1951, Serial No.236,580

2 Claims- (Cl. 110- 18) This invention relates to improvements in forceddraft incinerators for waste materiaLand more particularly to animproved corn cob burner, the primary object of the invention being toprovide a more practical and efficient device of this kind which lastslonger than conventional incinerators of this type,'is easier and lessexpensive to operate, substantially eliminates smoke and soot discharge,produces substantial- 1y less ash and residue to be cleaned out, andwhich can be constructed more quickly and with less expense formaterials and labor.

Another important object of the invention is to provide an incineratorof the above-indicated character which produces more rapid and com-Dlete combustion .of the material being incinerated at substantiallylower than usual wall temperature through provision for a cooling airblanket 'indrawn from the outside through wall openings and rising alongthe interior wall surfaces by reason or" the forced draft tuyere gratearrangement provided and by the natural rise of heated air in theinterior of the incinerator due to combustion. l

A further important object of the invention is to provide a hollow,vertical, open-top, cylindrical incinerator of the character indicatedabove, wherein the forced draft burner tuyere grate is located at thecenter of the incinerator,

away from the walls thereof, and provision is made for supplying thematerial tobe incinerated to the center of the incinerator immediatelyabove the grate in an arrangement such that the material is burnedalmost immediately and the burned material is deposited on the floor ofthe incinerator in an easily removable slag form in a circle around andconcentrically spaced from the grate, due to discharge of combustion airby the grate in both upward and lateraldirections.

Other important objects and advantageous fea-,

Figure 5 is a fragmentary, transverse, vertical section taken on theline 5-5 of Figure 2.

Referring in detail to the drawings, wherein like numerals designate'lze parts throughout the several views, the illustrated corn cobincinorator comprises a fireproof housing l, cylindrical in shape, itsdiameter and height to vary with the burning capacity required,comprising a poured reinforced concrete outer wall a fire brick liner 9,with asbestos mortar insulation iii between the brick and concrete, andwith a screen I! made of No. 9 galvanized wire in tension covered withsmall galvanised wire cloth l2 overthe top to arrest sparks arising as aresult of both natural and forced drafts, and designed principally forthe safe and effici nt burning of corn cobs at handling and shippingpoints. She forced draft is applied in the center of the housing 7 atground line 63 by a blower is located outside the housing, through aduct id installed below the dirt floor it of the housing, ex-

hausting through a cast tuyere grate ll, causing better combustion andmore rapid combustion. Air is also drawn by the effects of the naturaland forced drafts through vertically spaced rows of holes I8 in thewalls, which rises around the interior surfaces of the walls and reducesthe temperature against the walls. Cobs to be incinerated are suppliedthrough a declining spout ill in an opening Zil in the wall arranged todeposit the cobs near the center of the housing and over the tuyeregrate ll. At least one of the vertically spaced rows of openings 58 isdisposed above the level at which the lower end of the spout enters thehousing, and at least one other such row is disposed below this leveland between it and the top of the grate i l.

The concrete outer wall 8 is preferably only six inches thick, and thefire brick liner 9 is tures of the invention will be apparent from thefollowing description and the accompanying drawings, whereinior presentpurposes of i1lustration only, a specific embodiment of tion is setforth in detail.

In the drawings:

Figure 1 is a side elevation, partly broken away and partly in verticalsection, to show interior structure:

Figure 2 is an enlarged, fragmentary, top plan v1ew;

Figure 3 is a fragmentary, horizontal section taken on the line 33 ofFigure 1;

Figure 4' is a horizontal section taken on the line 4-4 of Figure 1; andI the invenpreferably only four and one-half inches thick, with'one-halfinch of asbestos mortar It between the concrete and brick, making atotal wail thickness of eleven inches. This compares with the generalpractice of having walls 32 1 inches thick at the bottom. Some of theadvantages of this reduction in wall thickness are lower first cost bothof materials and labor, and better radiation of heat, thus reducing thehigh internal wall temperature which otherwise causes the walls tocrack.

The tuyre grate H has a series of holes 21 in its horizontal top 22 forvertical discharge of air and is positioned above the floor I 5, and hasside openings 23 providing for horizontal discharge of air. Thisdelivery of oxygen will cause more perfect and more rapid combustion andalso cause the "hot spot of the fire to be in the center of the housingaway from the walls. This offers these advantages over the presentsystem of burning cobs. The hot spot is at the center of the housing,while in the conventional type it occurs at the walls, and thisexcessive heat at the walls damages them, even getting so hot that itwill melt the fire brick. Also the combustion is more nearly perfect,reducing the amount of ashes approximately 90 per cent, and burningthese ashes into a hard clinker. This clinker forms around the tuyeregrate ll without touching it, because of the lateral air blast blowingthe molten material away from the grate ll. This clinker resembles thecrater of a volcano, attaining a thickness of about 12 inches and adiameter of approximately five feet in three full days of burning. It isa very hard, glassy mass, easily broken up for removal. This reductionin ashes is advantageous because the burner does not have to be cleanedof ashes or residue so often, and each days burning starts withpractically a clean burner. The above-described forced draft also makesthe combustion more rapid and burns the cobs practically as fast as theyare supplied to the incinerator, thus avoidng any large accumulation ofcobs in the incinerator. Another benefit of the more nearly perfectcombustion thus attained is the elimination of practically all smoke andobnoxious gases which otherwise result from the slow imperfectcombustion in the conventional incinerators. This is a very importantadvantage, especially in cities having smoke ordinances with smokespotters on the job. The blower forcing in a supply of fresh cool airalso keeps the tuyere grate at an outside air temperature and preventsit from burning out,

The location of the forced draft in the center of the housing '5,together with the natural heat draft, creates a siphon jet action whichdraws cool air into the interior of the housing 7 through the holes 15in the wall. This cool air rises so as to form a curtain of cool airnear the wall and diminishes the heat on the walls, thus prolonging thelife of the housing i. type of incinerators, the hot air from the hotspots around the wall rises along the wall and heats it, causing thelining to expand and exert a pressure against the outer wall, causing itto crack and even in some instances bursts the steel bands placed aroundthe housing at different levels.

The insulating liner it, formed preferably of one-half inch of asbestosmortar, located between the brick liner 9 and the outside concrete wall8, is provided to insulate the heat from the concrete wall 8, and toprovide a cushion for the fire brick liners 9 to expand into, whenheated, thereby diminishing the outward pressure on the concrete wall 8.

The preferably e k-inch thick fire brick liner 9 is formed of brickslaid in a continuous spiral from the bottom to the top, with no mortarin the cross joints, the fire bricks to have only one side dipped in afluid fire clay mortar at time of placing in the wall. This contrastswith the usual practice of having fire brick liners ranging from 18inches thick at the base to nine inches thick at the top, with resultantsaving in much of the material and labor costs.

In the conventional cob incinerator the air for combustion is drawnthrough holes in the wall near the bottom. This causes slow combustionat the start and allows excessive quantities of cobs to accumulate inthe incinerator, which in time, after burning well, make a very hot firepro- In the conventional ducing an excessive amount of heat in thehousing, due to the quantity of cobs burning. Because of the location ofthese holes, the hottest spots are at the holes where the oxygen supplyis greatest. This is a great detriment to the housing, since it'appliesexcessive heat to the walls, causing them to crack, burst and burn out.Also, on account of the poor combustion in this type of burner,excessive amounts of smoke and obnoxious gases are given off, and crosswinds blowing through the vent holes above the fire pass out on theopposite side of the burner carrying smoke with them which smokes thewalls. In the present invention these faults are eliminated bytransferring the hot spot to the center of the housing by means of theblower Hi, duct l5 and tuyere burner grate l1, using the holes it in thwalls merely to supply cool air to bathe the walls and keep them cooler.In the drawings only three rows of vent holes are shown which weresuiiicient to prevent any smoke on the walls of a test apparatus. Due tothe upward rush of heat through the center of the housing drawing air inthrough the vents It, the outside of the apparatus remains clean. 7

The screen I I on top of the housing is formed by stretching No. 9galvanized wires 25 from pins 25 placed in the top of the concrete wallwhile it is being poured. These wires 25 are placed cif center so as toavoid building up at the center of the housing 1. Also, these wires 25being on a chord of the circle, the tension on the housing wall isnearer an end pull than a cross pull, avoiding a strain that would beproduced by a right angle mes-h tension which would cause verticalchecks on the outside concrete wall On top of this No. 9 galvanized wiresupport I lay strips 2! of small mesh galvanized wire cloth if? toarrest sparks from discharging from the top of the housing. Theadvantages of this type of screen are ease of installation, lower costboth of materials and labor, and being flush with the top of the housingwall makes all air and heat di charge vertically instead of having partof it subject to horizontal air currents through vertical sections ofthe screen projecting above the housing, as is the case in mostconventional burners. Due to the turbulence of the air caused by thecool air rushing in through the outside vents l8 and the amount of airsupplied by the blower M blending with the heated air from combustion inthe center of the housing, the heat is so reduced when it reaches thescreen i l, which is preferably 34 feet above the earth fioor it, thatit does not even effect the galvanizing on the wire of the screen II.

A banked dirt fill 28 is placed on the dirt floor l6 around the lowerend of the housing wall, except at the location of the clean-out openingwhich is provided in the housing wall at ground level. Ventilating andcooling holes iii surround the opening 20 through which the chargingspout l9 enters the housing 7, the inner end of the spout [9 being flushwith the interior surface of the housing wall, this arrangement beingprovided to prevent fire from traveling up the spout 59.

The shelling of 12,000 bushels of corn produces about 82 tons of cobs,which, when dui rped into a conventional burner in a days run, willsometimes fill such burner approximately half full. Since the-chargeburns at first at the top, the complete burning of the charge into thenight before a really hot and efficient fire develops, which requireswatching. This contrasts with the operation of the present invention,

5 wherein the cobs are burned almost as quickly as they are charged intothe burner and do not accumulate to any great extent in the burner.

What is claimed is:

1. man incinerator, a vertical cylindrical hollow housing having asubstantially plain cylindrical sidewall and being open at its upperend, a bottom wall closing the lower end of said housing, a tuyere gratemounted on and rising above said bottom wall and concentrically spacedfrom said sidewall, said grate being provided with side openings andwith top openings, means connected to said grate for supplying air underpressure to said grate to discharge air laterally toward the housingsidewall at the lower end of the housing and upwardly in the housing, adeclining charging spout having a lower end traversing the housingsidewall and entering the interior of the housing adjacent to the lowerend of the housing and on a level above said grate, the housing sidewallbeing provided with a plurality of horizontal rows of circumferentiallyspaced outside air intake openings, one of said rows of air intakeopenings being located on a level between the lower end of the chargingspout and said grate, and another row of air intake openings beinglocated on a level immediately above the lower end of the chargingspout.

2. In an incinerator, a vertical cylindrical hollow housing having asubstantially plain cylindrical side wall and being open at its upperend, a bottom wall closing the lower end of said housing, a tuyre gratemounted on and rising above said bottom wall and concentrically spacedfrom said sidewall, said grate being provided with side openings andwith top openings, means connected to said grate for supplying air underpressure to said grate to discharge air laterally toward the housingsidewall at the lower end of the housing and upwardly in the housing, adeclining charging spout havhig a lower end traversing the housingsidewall and entering the interior of the housing adjacent to the lowerend of the housing and on a level above said grate, the housing sidewall being provided with a plurality of horizontal rows ofcircumferentially spaced outside air intake openings, one of said rowsof air intake openings being located on a level between the lower end ofthe charging spout and said grate, and another row of air intakeopenings being located on a level immediately above the lower end of thecharging spout, the sidewall of the housing being otherwise imperforate,

WALTER C. POLK.

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